No, 82 

1958 

TIMELY SALVAGE CAN REDUCE LOSSES 

FROM BEECH SCALE-NECTRIA ATTACK 

Beech is one of our more common hardwoods. It is an 

important component of the northern hardwood forest type, 

which occupies about29percent of the commercial forest land 

in the New England and Middle Atlantic States, In terms of 

total sawtimber volume, beech follows close on sugar maple, 

red oak, and yellow birch. It is used for a variety of products such as furniture,handles, flooring, containers, dowels, 

shuttles, and spools. In recent years, more beech has been 

used in woodpulp production; and with new processing techniques, it may become even more valuable for pulp. For these 

reasons, plus the growing emphasis on quality timber, forest 

managers should look carefully at their beech stands and 

this tree's most serious enemy: the beech scale-Nectria complex. 

Beech Scale-Nectria Complex 

The beech scale is a tiny, yellow insect, covered by 

a white woolly wax that it secretes. Light attacks of scale 

appear as isolated, white woolly dots on the bark of the 

tree, usually near the base. As infestation increases, the 

dots form thin vertical lines and then solid patches. Heavy 

infestations may completely cover the trunk and lower sides 

of branches with a whitish woolly mass. 

The Nectria is a fungus. It appears on the bark as 

clusters of tiny, red, lemon-shaped fruiting bodies about the 

size of a pin head. These bodies first occur as single 

clusters, later in patches. When present in large numbers, 

they give a reddish tinge to the tree trunk. 
Nature of Damaee 

As far as is known, neither organism alone wlll kill 

trees. The insect damages the bark cells by feeding. This 

causes the cells to dry out; and cracks appear in the bark, 

through which the Nectria gains entrance, The Nectria penetrates the cambium and sapwood, finally killing the tree by 

girdling. Thus both the scale and the fungus operating together are necessary to kill trees. 

Distribution of Beech Scale-Nectria 

Both the beech scale (insect) and the Nectria (fungus) 

are of European origin and were introduced into North America nearly 70 years ago. Scale was first found near Halifax, 

Nova Scotia, about 1890; and, although the Nectria was not 

discovered until 1929, it is suspected that both organisms 

arrived here together. During the past half-century, they 

have spread south and west throughout the Maritime Provinces 

of Canada, across Maine, into the White and Green Mountains 

of New Hampshire and Vermont, and down into the Catskills of 

New York. 

The scale has been found in several localities in 

Massachusetts and Connecticut. In 1955 the Nectria was even 

noted on a tree in West Virginia. Thus far, neither scale 

nor Nectira has been found in Pennsylvania, although both 

occur in bordering Sullivan County, N.Y. 

Extreme cold has apparently prevented spreading of 

the scale to the North. It has not been found in northern 

Maine or the Adirondacks. 

Extent of Damane 

Extensive mortality of beech has already occurred in 

Maine as a result of beech scale-Nectria attack. It has been 

estimated that about 24 percent of the beech in that state 

has been killed and another 16 percent is dying. In some 

small areas, 97 percent tree mortality has occurred, Heavily 

attacked beech in the White Mountains and the Catskills are 

already dying and extensive killing may be expected there in 

the near future. Tree killing seems imminent in certain 

sections of the Green Mountains. 

Natural Control 

Severe winter temperatures of -35"~ and lower are 

lethal to beech scale. When such temperature extremes occur, 

practically all scales above the snow line are killed. No 

parasites of the scale are known, but a predaceous ladybird 

beetle is prevalent throughout the range of the insect. 
Where scale infestation is light, this beetle appears capable 

of delaying buildup of the scale. But in heavy infestations, 

the beetle has little value as a controlling agent. Scale 

populations are usually heavier in dense forest stands than 

in open, park-like areas. 

Chemical Control 

Any attempt at chemical control of the scale would 

involve spraying the bark of individual infested beeches. 

Obviously, spraying commercial forest stands would be impractical because of the difficulty and expense of the operation. Tests have shown that the scale may be controlled 

with a number of chemicals--DDT, lime-sulphur, etc.--and 

under certain circumstances, such as in parks or areas of 

high recreational value, it is possible to protect trees by 

spraying. 

Silvicultural Control 

A study was undertaken in 1952 on the Bartlett Experimental Forest to determine if the scale population could be 

controlled by regulating the density of the stand. Within 

the experimental stand, several areas were opened up in 

varying degrees by removing from one-fifth to one-half of 

the basal area. In one section where one-half of the basal 

area was removed, the undergrowth was mowed. In all areas, 

little or no beech was cut. 

At the time the study was started, heavy scale attack 

occurred on about one-third of the trees and light scale on 

the rest. No Nectria was found. Observations on scale and 

Nectria abundance have been made each fall since 1952. 

In 1956, after 4 years, there was no indication that 

regulation of stand density (opening up the stand) had had 

any effect on scale abundance on trees heavily infested in 

1952. On lightly infested trees, there was a slight reduction in scale population in heavily cut areas, particularly 

on smaller trees. In the medium and lightly cut areas, there 

was no apparent difference in scale abundance in 1956 than 

in an adjacent uncut stand. 

During the first 4 years, regardless of the degree of 

cutting, Nectria increased on about four-fifths of the trees 

that had originally been heavily infested. Still, in the 

heavily cut areas fewer trees developed Nectria. This was 

quite noticeable on trees under 9 inches in diameter. And 

there was even a slight reduction in Nectria on some trees. 

But mediumand light cuts apparently had no effect on Nectria 

abundanceo 
Observations made elsewhere in New Hampshire indicated that heavy thinning resulted in a slight reduction in 

the rate of increase of both organisms. 

Thus, heavy scale infestation or Nectria infection 

was not markedly reduced by opening up the stand. And even 

in young beech stands, lightly infested with the scale, removal of about one-half of the basal area would be required 

to produce any beneficial results. Such a heavy cut might 

be of questionable silvicultural value in stands containing 

species, such as birch, that have a tendency to deteriorate 

after a heavy cut. 

What Can Be Done? 

So far no chemical or silvicultural methods have been 

developed for controlling the scale under forest conditions. 

But timber losses may be minimimized through timely salvage 

cuts. No precise time table for such cuttings can be given 

because buildup of both scale and Nectria depends on many 

circumstances. Probably the stand itself is most important: 

its location, site, and density; the size and age of the 

trees; and the severity of scale and Nectria attack at the 

time of discovery. 

Certain general principles based on observations in 

unthinned stands on the Bartlett Experimental Forest may be 

followed: 

Salvage cuttings may be delayed for a period of 5 to 8 

years after a light scale attack is first noticed. 

In areas where heavy scale is present, a high percentage of the trees will become infected with Nectria 

within 2 years and tree mortality may be expected soon 

thereafter. In such stands cutting should not be delayed more than 3 or 4 years after heavy scale attack 

is first observed, 

In areas where Nectria attack is already present, salvage cuts should be undertaken at once, 

These three guide-lines are not intended to be the 

last word and may not suit all stands. However, they are 

offered as a general time table for salvage cuttings in 

stands where the beech scale or Nectria is found. 

--DAVID CROSBY and J. C. BJORKBOM 

Northeastern Forest Experiment Station 

Forest Service, U,S, Dept. Agriculture 

AGRICULTURE.FOREST SERVICE-UPPER DARBY